U.S. Pat. No. 3,840,016 has an electrocoagulation device for intrauterine sterilization of the fallopian tube using a monopolar electrode and temperature control of just the electrode. U.S. Pat. No. 4,057,063 has a monopolar catheter to treat the fallopian tubes with impedance increase monitoring to assess the completion of treatment.
U.S. Pat. No. 4,411,266 is an RF lesioning electrode with temperature sensor in the conductive tip. The system is monopolar. U.S. Pat. No. 5,486,161 is an RF probe with heating through a hollow needle tip in monopolar fashion. U.S. Pat. No. 4,057,063 senses impedance of tissue in the vicinity of a monopolar electrode with a 5 second activation at 4.8 W with no control to lesion the entry from uterus to fallopian tubes.
U.S. Pat. No. 5,122,137 has a monopolar RF electrode with a temperature sensor buried therein. Circuitry measures temperature when the RF power is off. This electrode is used to thermally occlude the fallopian tubes.
U.S. Pat. No. 5,303,719 includes a delivery system for laser, electrical power or adhesive to the fallopian tubes. The electrical modality is monopolar.
U.S. Pat. No. 4,685,459 has bipolar forceps with temperature sensors on the electrodes to limit the maximum temperature of the tissue contacted during RF coagulation. U.S. Pat. No. 4,685,459 is a bipolar forceps device with power controlled to the faces by buried thermal probes in the faces of the opposing forceps ends.
U.S. Pat. No. 4,700,701 is an electrically energized cautery of the fallopian tube followed by insertion of a plug. U.S. Pat. No. 5,095,917 has a bipolar RF catheter to lesion superficially the mucosa layer near the uterotubal junction before a porous plug is inserted and there is no control of power and no monitoring during RF activation. U.S. Pat. No. 5,303,719 destroys the inner layer of cells in fallopian tube and then uses suction to collapse and adhere the walls but there is no mention of RF energy of control.
U.S. Pat. No. 4,587,975 has an angioplasty catheter with cylindrical electrodes used for recording impedance plethysmography. A thermal cautery probe for blood vessels with a resistive heater does not have RF. It is temperature controlled by using a diode breakdown voltage. U.S. Pat. No. 5,122,137 concentrates current in the vicinity of an electrode which must be thermally conductive due to the thermocouple buried inside herein a multiple electrode configuration has each electrode sensed.
Female sterilization for the prevention of pregnancy may be a necessary procedure performed laparoscopically with electrosurgery. Typically, the fallopian tubes are grasped with bipolar forceps on the outside of the tube and electrosurgical energy is applied over a period of time until the surgeon sees the tubes coagulate. Following this, a second and third coagulation made on either side of the original extend the length of the coagulation.
Several papers, published since 1878, disclose procedures that attempt to use heat to close the fallopian tubes. A hot probe cauterized the opening of the fallopian tube from the uterus (tubal osteum). Later techniques with uncontrolled monopolar RF energy delivery sometimes failed. The use of a bipolar probe followed by placement of a plug in uterine opening of the fallopian tube had no control of power and an uninsulated tip of 1.5 mm length, thus operating at the edge of the fallopian tube and not farther inside the tube.
Sterilization requires certainty with respect to the apparatus and the procedure used. The background herein discusses devices which fail to provide a level of certainty because the idea for each of the identified prior techniques and instruments was to seal the fallopian tubes with the treatment. The less invasive approach disclosed herein recognizes that natural healing will produce a superior, reliable, atraumatic and consistent result not found in the prior patents or literature.
Another use for this bipolar RF catheter device is for controlled use in blood vessels for embolotherapy. This would include sealing of arterial feeder vessels that communicate with tumors in order to reduce the blood supply to the tumor either prior to surgery or as a treatment to necrose the tumor. In cases where congenitally formed vessels are anomalous, these would be sealed off by this catheter device. In the lung, anomalous vessels shunt blood flow and need to be closed. Arterovenous fistulas, pseudoaneurysms caused by trauma or infection, hepatic artery-bile duct fistulas or sites of active hemorrhage are also applications for this device. In all of these examples, the application of RF energy will thrombose and occlude the vessel by heating the blood and the vessel wall to provide closure or sealing. Symptomatic arterovenous malformations in the uterus is often treated by hysterectomy since it otherwise results in massive vaginal bleeding and spontaneous abortions. Embolization can prevent these outcomes. Massive vascular hemorrhage can result in multi-organ failure. Many of these patients are not candidates for surgery.
Several methods have been tried to occlude vessels. These include placing polyvinyl alcohol particles or metal flakes, degradable starch, cyanoacrylate, ethanol, detachable balloons, small coils or gelatin sponges. These techniques all deal with a foreign body left behind with potential to migrate or flow out of the intended site. Recanalization can also result with some of these techniques. Precise control of coils during positioning or withdrawal is often challenging. Non-target tissue embolization results in tissue devitalization of normal structures. The only techniques described in the medical literature for thermal embolization are the use of iron microspheres which are heated in an external radiofrequency field at 100 kHz. Another technique was to use hot contrast agents, as used in angiography, heated to 100 C. Yet another technique used a laser with a metal cap to thrombose with heat and then leave the metal cap permanently in place.
U.S. Pat. No. 5,053,006 discusses permanent occlusion of arteries using a laser. The technique involves injecting a dye into the vessel and then introducing laser light at a wavelength to perform photochemical injury to the vascular endothelium. U.S. Pat. No. 5,108,407 suggests placing a coil for embolization connected to a fiberoptic cable. Laser energy is introduced into the cable to melt the adhesive and release the coil. U.S. Pat. No. 5,354,295 also involves a coil placed for endovascular occlusion. The coil is then heated by flowing current between the electrode and the tip. Energy is activated until the wire disconnects from the coil. There is no mention of RF energy and the unit is not bipolar.
U.S. Pat. No. 5,405,322 uses a balloon to heat the wall of an aneurysm. RF current flows between the electrodes to heat the fluid in the balloon which then heats tissue through thermal conduction. There is no RF energy flowing through tissue. U.S. Pat. No. 5,437,664 is a device for occluding the lumen of veins. The electrode is energized in a monopolar fashion and may utilize impedance or temperature to signal the end of the treatment. No temperature of impedance endpoints are suggested. There is no control of power but only shutoff when endpoints are achieved.
The device described here will embolize by inserting the device into the vessel and precisely applying radiofrequency energy to heat the blood in the vessel to a controlled temperature for thrombosis and sealing of the vessel to occur. This autologous clot will not cause any foreign body reaction since nothing is left behind after the removal of the catheter.